Fin tube



Jay 2%,, 1947. A. Y. GUNTER FIN-TUBE Filed Dec. 22, 1943 FIG. I

INVENTOR Add/50 Y Gunief i a b m- M W Patented July 29,

' UNITED Addison Y. Gunter, Larchniont, N. Y., assignor to. American Locomotive Company, New York, N. Y., a corporation of New York Application December 22, 194a, Serial No. 515,265

This invention relates to flhr-tubes, and more. particularly to a tin-tube having novel internal cup-shape wire screen flns, the bottoms ofthe cups providing spaced cross fins. p

It is known to employ flat discs of wire screen entirely filling the interior .of a tube and engaging each other for support to increase the heat-conducting surfaceo! the tube,no attachment to the tube being provided. Because of the number of discs employed and the consequent rehad to be made larger in orderto provide for the necessary flow ratetherethro'ugh. Moreover, due

to the fact that the discs are not attached to the tube, heat transfer from these fin-like discs is. not efficient, I y The present invention is directed toward pro viding a. tin-tube having internal cup-shape wire screen flns, the; bottoms of the cups providing spaced cross fins through which ample flow can take place without the necessity of enlarging the tube. Accordingly, an object of the present invention is to provide a fin-tube having internal cup-shape wire screen fins, each having a flange,

the flanges insuring spacing of the transverse bottoms of the cups and providing for bondingof the cups to the inner face of the tubular member of the tube.

Other and further objects of this invention will appear from the following description, the accompanying drawing and the appended claima cups shown in the tube of Fig. l; and Fig. 4 is an enlarged vertical central sectional view of .a portion of a completed fin-tube.

The present invention concerns the fln-tube. indicated generally by the reference numeral I,

shown in Fig. 4,. Tube I includes a tubular memher 2, and wire screen cups 3 secured transversely in the tube, as by soldering. Cups 3 provide internal cross fins for the tube for increasing its.- effective heat exchange surface and provide i'or' increased turbulence which promotes increased heat transfer, the wires of the cup' forming, in effect, pin fins in the tubular member.

1 Claim. cuss-as) 1 Each wire screen cup includes a transverse flat bottom portion 4 and an integral circular perpendicular flange 5. The wires of the flange are preferably, but not necessarily, flattened circum- 5 ferentially of the flange at their ends and" at pointswhere wires cross each other, as is indicated in the drawingby the letter a, to prevent flange wires being broken when the flanges are formed. The cups are disposed similarly in the tubular member in engagement witheach other duction intheflow area of the tube. the tube over the finned length of the tube, each flange 5 at its outer edge engaging the adjacent cup. Thus flanges 5 serve to correctly space the transverse portions 4. They also serve to provide adelli quate surface for insuring a secure bond between the cups and the tubular member. That is to ends'of thewires of portions 4 would have to be bonded to the tubular member wall and it would 10' be diflicult to insure perfect bonding of each wire f to the wall. The flattened portions of flanges 5 also aid materially in obtaining a secure bond between the tubular member, and the cups. The

wires of the flanges provide added fln surface which extends over the entire inner surface of the tubular member when the cups are disposed as shown. Referring to Fig, 1, the apparatus-shown therein includes a forming blockG having an upper face I and a lower face 8; A shouldered recess forming a die 9 is formed in the face I and is of the proper diameter to produce a screen blank "Ill, best shown in Fig. 2. A shear punch II coacts with die 9 to punch the blank I 0 outof a sheet of wire screen I2, as is clearly shown in Fig. 1, Punch II not only cuts the blank I0 out 1 of the sheet I 2 but further, when desired, may

be employed to press its margin firmly against the horizontal face of the die 9, thereby flattening 40 the wires engaged between the die and the punch which provide the flange of the iin cup, as shown in the drawing. I

Block 6 also includes an orifice providing a. die I3 adjacent die 9 and of smaller diameter, the diameter being proper to produce the cups 3. Punchll is bored and a forming bar It operates in this bore to engage the blank l0 disposed in die Sand force it into die I3 in an obvious manner to form the flanges of the cups 3, the pressure of the punch I I being first released and the diameter of the bar I4 being sufliciently less than the diameter ofthe die I3 to permit formation of the flange.

A shouldered recess forming a jig I5 is formed in face 8 of block 6 below die I3, and is of a diameter larger than the die I3 and proper to receive the tubular member '2. Tubular member 2 has an inside diameter equal to the diameter of die i3 and aligned therewith. Bar I4 has a stroke suflicient to enter tubular member 2,"pushing the cup it has formed into the tubular member 2 to a desired position.

The bar I, die 9, die 13, and jig 15 are disposed in line with each other. The apparatus has been but briefly described as it forms no part of the present invention.

After the tubular member has been filled with the desired number 01 cups, the cups are bonded to the wall of the tubular member. It has been found that a suitable bond may be formed by pretinning the inner wall of the tubular member and of the wire screen, and then heating the tubular member with the cups therein in a furnace-to a bonding temperature. Pretinning the wire screen also bonds all the wires together at their points of crossing.

approved embodiment of this invention, it will be understood that many andv various changes and modifications in form, arrangement of parts and details of construction thereof may be made without departing from the spirit of the inven- While there has been'hereinbefore described an tion, and that all such changes and modificav tions as fall within the scope oi! the appended claim are contemplated as a part of this invention.

The invention claimed and desired to be secured by Letters Patent is:

A fln-tube comprising a tubular member; and a plurality of wire screen cups in said tubular member, each of said cups having a wire screen bottom extending transversely of said tubular member and a circumrerentially continuous wire screen side flange integral with and at right angles to said bottom, said cups being arranged in succession with the flanges of successive cups being each in engagement at its free edge with the bottom of the cup adjacent thereto, each of said flanges being 'bonded throughout to said tubular member whereby said cup flanges collectively provide a substantially continuous wire screen sleeve bonded to the inner face of said tubular member, the wires of said wire screen sleeve extending the heat exchange surface of the inner face of said tubular member and the wires of said wire screen bottoms further extending said heat exchange surface of said inner face or said tubular member.

ADDISON Y. GUNTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Austria Mar. 26, 1902 

